Adhesive compositions for use in die attach applications

ABSTRACT

Novel adhesive compositions that can be used in the die attach process. The adhesives include a curable resin component, a curing agent, and a block copolymer additive. The block copolymer additive has a glass transition temperature of at least about 40° C. The block copolymer additive improves the affinity of the adhesive composition to a hydrophilic substrate, such as a silicon wafer, during the die pickup process. Also disclosed is an assembly which includes a hydrophilic substrate and a layer of adhesive and methods of producing the assembly.

RELATED APPLICATIONS

The present application is a divisional application of U.S. applicationSer. No. 12/884,300, filed Sep. 17, 2010, now issued as U.S. Pat. No.8,338,536, which is a continuation of PCT/US2009/037246, filed Mar. 16,2009, which, in turn, claims priority from U.S. Application No.61/037,096, filed Mar. 17, 2008, the entire contents of each of whichare hereby incorporated by reference herein in their entirety.

BACKGROUND

1. Field

Adhesive compositions are provided and more specifically adhesivecompositions useful in the die attach process. The adhesive compositionsexhibit excellent adhesive film release and die attach properties whilealso exhibiting void-free coverage in die attach applications.

2. Related Technology

Adhesive compositions play a prominent role in many industrialapplications. For example, in the electronics industry, packagingengineers faced with increased challenges of finding new and better waysof creating and attaching dies during the dicing and subsequent dieplacement processes often rely on adhesive compositions to secure asilicon wafer to a dicing substrate during the dicing process and alsoto secure the individual diced chips to a circuit board or othersubstrate during die placement. Numerous adhesive compositions have beenproposed for use in such die attach processes, including those describedin one or more of U.S. Pat. No. 7,162,110 (Kohinata et al.), U.S. Pat.No. 7,312,534 (Santos et al.), and U.S. Pat. No. 7,176,044 (Forray etal.).

Those adhesives generally include a curable base component and one ormore additives that provide the composition with unique properties. Forexample, additives are known to improve conductivity, reduce cure time,and provide a stronger interface bond after die placement has occurred.However, these adhesives do not adequately address certain problemsassociated with some of the current operations in the die attachindustry.

For example, dicing die attach films, which are composed of a dicingtape layer and an adhesive layer on top of the tape layer, areincreasingly being used in the dicing and die attach process. In use, apre-diced silicon wafer is placed onto the adhesive layer of such afilm, dicing of the wafer and the adhesive layer is completed, and theindividual chip dies are removed from the tape layer of the film usingconventional die pickup methods. Ideally, the layer of adhesive, whichis also diced during the dicing process, transfers from the dicing tapeto the chip die so that the chip die can subsequently be placed directlyat another location without first dispensing a new layer of adhesive onthe chip die or at the new placement location.

However, because of the nature of the adhesives currently used to formthe adhesive layer in these dicing die attach films, adequate transferof the adhesive from the dicing tape layer to the chip die surface doesnot always occur. Furthermore, because the adhesives used in theadhesive layer are composed of high molecular weight resins, the flowproperties of such adhesives are oftentimes insufficient to create avoid-free bond interface between the chip die and the substrate afterthe subsequent die placement and curing steps for die attachment.

Thus, there remains a need for novel adhesive compositions which includeadditives that provide unique advantages over those adhesivecompositions that are currently known, particularly adhesives thatbetter facilitate the transfer of the adhesive layer to the die duringthe die pickup process and allow for the formation a void-free bondafter die placement.

SUMMARY

In one aspect an adhesive composition is provided, and in particular anadhesive composition that includes a curable resin component, a curingagent, and a block copolymer additive that is comprised of hydrophilicand hydrophobic segments where the additive has a glass transitiontemperature of at least about 40° C., such as between about 60 and 150°C.

In one embodiment, the ratio of the hydrophobic segments to thehydrophilic segments in the block copolymer additive is at least 2:1 andin another embodiment this ratio is between 3:1 and 12:1.

In another aspect, the hydrophilic segments contain O or N atoms, and inone embodiment the hydrophilic segment is an anhydride, such as maleicanhydride.

In yet another embodiment, the hydrophobic segments include at least onepolyolefin, examples of which include ethylene, propylene, 1-butene,1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, and styrene.

In another aspect, an assembly comprised of a hydrophilic substrate,which may be a silicon wafer, and an adhesive composition is provided.The adhesive composition includes a curable resin component, a curingagent, and a block copolymer additive that is comprised of hydrophilicand hydrophobic segments in a ratio of at least 2 hydrophobic segmentsto every 1 hydrophilic segment.

In another aspect, a method of forming an assembly comprising ahydrophilic substrate and an adhesive composition that includes acurable resin component, a curing agent, and a block copolymer additivethat is comprised of hydrophilic and hydrophobic segments in a ratio ofat least 2 hydrophobic segments to every 1 hydrophilic segment isprovided.

In another aspect, a composition including:

-   -   An epoxy component;    -   A silane-modified epoxy component;    -   A thermoplastic urethane; and    -   Diaminodiphenyl sulfone,        is provided, which may be in the form of a pre-applied adhesive.

In another aspect, a composition of matter is provided that includes:

-   -   As component (A) an epoxy component embraced by the following        structure:

where Y may or may not be present and when Y present is a direct bond,CH₂, CH(CH₃)₂, C═O, or S, R₁ here is alkyl, alkenyl, hydroxy, carboxyand halogen, and x here is 1-4;

-   -   As component (B) an epoxy-functionalized alkoxy silane embraced        by the following structure:        R¹—Si(OR²)₃  (VIII)        where R¹ is an oxirane-containing moiety and R² is an alkyl or        alkoxy-substituted alkyl, aryl, or aralkyl group having from one        to ten carbon atoms; and    -   As component (C) reaction products of components (A) and (B) is        provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of an assembly.

FIG. 2 is a schematic representation of a dicing die attach film thatmay be used in forming an assembly.

FIG. 3 is a schematic representation of one embodiment of the method offorming the assembly using the dicing die attach film of FIG. 2.

FIG. 4 is a schematic representation of another embodiment of the methodof forming the assembly using an ink jet printing application.

FIG. 5 depicts a synthetic scheme by which the silane modified epoxydiscussed herein may be prepared.

DETAILED DESCRIPTION

As used herein, spatial or directional terms, such as “left”, “right”,“inner”, “outer”, “above”, “below”, “top”, “bottom”, and the like,relate to the invention as it is shown in FIG. 1. However, it is to beunderstood that the invention may assume various alternativeorientations and, accordingly, such terms are not to be considered aslimiting. Further, as used herein, all numbers expressing dimensions,physical characteristics, processing parameters, quantities ofingredients, reaction conditions, and the like, used in thespecification and claims are to be understood as being modified in allinstances by the term “about”. Accordingly, unless indicated to thecontrary, the numerical values set forth in the following specificationand claims are approximations that may vary depending upon the desiredproperties sought to be obtained by the present invention. At the veryleast, and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, each numerical value should atleast be construed in light of the number of reported significant digitsand by applying ordinary rounding techniques. Moreover, all rangesdisclosed herein are to be understood to include the beginning andending range values and to encompass any and all subranges subsumedtherein. For example, a stated range of “1 to 10” should be consideredto include any and all subranges between (and inclusive of) the minimumvalue of 1 and the maximum value of 10; that is, all subranges beginningwith a minimum value of 1 or more and ending with a maximum value of 10or less, e.g., 5.5 to 10.

A composition of matter and, in one particular embodiment, an adhesivecomposition, such as for use in die attach applications is provided. Theadhesive composition includes a curable resin component, a curing agent,and a block copolymer additive comprised of hydrophilic and hydrophobicsegments. The block copolymer additive of the present invention acts asa “release agent” by increasing the affinity of the adhesive compositionfor a hydrophilic substrate, such as a hydrophilic silicon wafer,compared to a hydrophobic substrate, such as a hydrophobic polyolefindicing tape. This effect makes the adhesive composition of the instantinvention particularly desirable for use in the die attach industry. Forinstance, if the adhesive composition of the present invention is usedto secure a hydrophilic pre-diced wafer to a hydrophobic dicing tapeduring dicing, the adhesive layer will transfer, or release, from thedicing tape to the surface of the chip dies upon removal of theindividual dies from the dicing tape. This allows for immediateattachment of the chip dies onto another substrate and eliminates theneed for subsequent dispensing of additional adhesive layers prior tosuch attachment.

For purposes of this application, a hydrophilic segment is defined as amoiety of a polymer that can be generally described as charge polarized,or polar, and capable of hydrogen bonding with, for example, watermolecules. When used in describing a substrate, a hydrophilic substrateis one that is wettable upon contact with a polar liquid, such as water.A hydrophobic segment is a polymer moiety that is non-polar, or chargeneutral, and typically incapable of fully dissolving in polar solvents.

As noted, the adhesive composition of the present invention includes acurable resin component. The curable resin component can be any curableresin, and is desirably a thermosetting polymeric material that curesthrough the addition of energy, such as heat or irradiation, to astronger form. Particularly useful are thermosetting resins that arecapable of undergoing a partial cure, such as through a B-stagingprocess, to form a partial reaction product, in a tackified form.Examples of useful curable resins include epoxies, episulfides,maleimides, itaconimides, nadimides, (meth)acrylates, and combinationsthereof.

If the resin component is selected to include an epoxy, anythermosetting epoxy resin may be used which is capable of beingpartially cured or B-staged, as will be discussed in more detail herein.Particularly desirable are solid epoxy resins and, in particular, tri-or multi-functional epoxy resins. Non-limiting examples of useful epoxyresins include solid epoxy resins derived from bisphenol A, F, or S,tetramethylbiphenyl and/or biphenyl, and epichlorohydrin, novolacs, andthe like. Triglycidyl isocyanurate (“TGIC”) is particularly desirable, acommercially available example of which istris(2,3-epoxy-propyl)isocyanurate, sold under the tradenaine TEPIC® byNissan Chemical Industries, Ltd. Also desirable is a dicyclopentadiene(“DCPD”) epoxy, an example of which is Tactix® 556 from HuntsmanChemical. Combinations of epoxy resins can also be used.

Examples of other useful epoxies include those embraced by structures Iand II below.

In structures I and II, X can be present at least once on structure I(i.e., mono-, di-, or tri-substituted) and itself may be chosen from Hor D_(n)A, where n can range between 0 and 1, with at least one X beingD_(n)A. D, if present (i.e., if n=1), can be attached to the ring andcan be chosen from O, S, or NH. A can be attached to D (if present) ordirectly to the ring (if D is not present, i.e., n=0). A can berepresented by structure III below:

where E can be a member selected from H, alkyl, alkenyl, alkynyl, and/oralkoxy groups which may be linear, branched, or cyclic, and/or arylgroups, having from 1 to 20 carbon atoms with or without substitution byhalogen, silicon, hydroxy, nitrile, ester, amide, or sulfate. R can beselected from H, alkyl, alkenyl, alkynyl, and/or alkoxy groups which maybe linear, branched, or cyclic, and aryl groups, having from 1 to about20 carbon atoms, with or without substitution by halogen, nitrogen,silicon, hydroxy, nitrile, ester, amide, or sulfate.

X₁ can be present at least once on structure II (i.e., mono-, di-, ortri-substituted) and itself may be chosen from H or O═CD_(n)A with atleast one X₁ being O═CD_(n)A, where D_(n) and A can be as defined above.

Another suitable epoxy is embraced by

where D and A can be as described above and can be present at least onceand can also be present together attached to ring atoms which are inalpha-beta relation to one another.

Examples of particular epoxies thus include, but are not limited to,those embraced in formulas V-VII below.

Also particularly desirable are silane-modified epoxies. One suchsilane-modified epoxy is formed as the reaction product of an aromaticepoxy, such as a bisphenol A, E, F or S epoxy or biphenyl epoxy, andepoxy silane where the epoxy silane is embraced by structure VIII:R¹—Si(OR²)₃  (VIII)where R¹ is an oxirane-containing moiety, examples of which include2-(ethoxymethyl)oxirane, 2-(propoxymethyl)oxirane,2-(methoxymethyl)oxirane, and 2-(3-methoxypropyl)oxirane and R² is analkyl or alkoxy-substituted alkyl, aryl, or aralkyl group having fromone to ten carbon atoms. In one embodiment, R¹ is2-(ethoxymethyl)oxirane and R² is methyl.

Idealized structures of the aromatic epoxy used to prepare the silanemodified epoxy include

where Y may or may not be present and when Y present is a direct bond,CH₂, CH(CH₃)₂, C═O, or S, R₁ here is alkyl, alkenyl, hydroxy, carboxyand halogen, and x here is 1-4. Of course, when x is 2-4, chain extendedversions of the aromatic epoxy are also contemplated as being embracedby this structure.

For instance, a chain extended version of the aromatic epoxy may beembraced by the structure below

The silane modified epoxy may also be a combination of the aromaticepoxy, the epoxy silane, and reaction products of the aromatic epoxy andthe epoxy silane. The reaction products may be prepared from thearomatic epoxy and epoxy silane in a by weight ratio of 1:100 to 100:1,such as a by weight ratio of 1:10 to 10:1.

In addition to epoxies, episulfides are desirable as well, whether theyare full or partial episulfides, provided that they are in the solidstate. Episulfides may be commercially available or readily preparedfrom the corresponding epoxy through known synthetic methods.

Maleimides, nadimides, and itaconimides are also useful as the curableresin, including those compounds having the following structures IX, X,and XI, respectively:

where m can range from 1 to 15, p can range from 0 to 15, each R² isindependently selected from hydrogen or lower alkyl, and J is amonovalent or a polyvalent moiety comprising organic or organosiloxaneradicals, and combinations of two or more thereof.

More specific representations of the maleimides, itaconimides, andnadimides in the solid state include those corresponding to structuresIX, X, or XI, where m ranges from 1 to 6, p is 0, R² is independentlyselected from hydrogen or lower alkyl, and J is a monovalent orpolyvalent radical selected from hydrocarbyl, substituted hydrocarbyl,heteroatom-containing hydrocarbyl, substituted heteroatom-containinghydrocarbyl, hydrocarbylene, substituted hydrocarbylene,heteroatom-containing hydrocarbylene, substituted heteroatom-containinghydrocarbylene, polysiloxane, polysiloxane-polyurethane block copolymer,and combinations of two or more thereof, optionally containing one ormore linkers selected from a covalent bond, —O—, —S—, —NR—, —O—C(O)—,—O—C(O)—O—, —O—C(O)—NR—, —NR—C(O)—, —NR—C(O)—O—, —NR—C(O)—NR—, —S—C(O)—,—S—C(O)—O—, —S—C(O)—NR—, —S(O)—, —S(O)₂—, —O—S(O)₂—, —O—S(O)₂—O—,—O—S(O)₂—NR—, —O—S(O)—, —O—S(O)—O—, —O—S(O)—NR—, —O—NR—C(O)—,—O—NR—C(O)—O—, —O—NR—C(O)—NR—, —NR—O—C(O)—, —NR—O—C(O)—O—,—NR—O—C(O)—NR—, —O—NR—C(S)—, —O—NR—C(S)—O—, —O—NR—C(S)—NR—, —NR—O—C(S)—,—NR—O—C(S)—O—, —NR—O—C(S)—NR—, —O—C(S)—, —O—C(S)—O—, —O—C(S)—NR—,—NR—C(S)—, —NR—C(S)—O—, —NR—C(S)—NR—, —S—S(O)₂—, —S—S(O)₂—O—,—S—S(O)₂—NR—, —NR—O—S(O)—, —NR—O—S(O)—O—, —NR—O—S(O)—NR—, —NR—O—S(O)₂—,—NR—O—S(O)₂—O—, —NR—O—S(O)₂—NR—, —O—NR—S(O)—, —O—NR—S(O)—O—,—O—NR—S(O)—NR—, —O—NR—S(O)₂—O—, —O—NR—S(O)₂—NR—, —O—NR—S(O)₂—,—O—P(O)R₂O—, —S—P(O)R₂—, —NR—P(O)R₂—, where each R is independentlyhydrogen, alkyl or substituted alkyl, and combinations of any two ormore thereof.

When one or more of the above described monovalent or polyvalent groupscontain one or more of the above described linkers to form the “J”appendage of a maleimide, nadimide, or itaconimide group, as readilyrecognized by those of skill in the art, a wide variety of linkers canbe produced, such as, for example, oxyalkyl, thioalkyl, aminoalkyl,carboxylalkyl, oxyalkenyl, thioalkenyl, aminoalkenyl, carboxyalkenyl,oxyalkynyl, thioalkynyl, aminoalkynyl, carboxyalkynyl, oxycycloalkyl,thiocycloalkyl, aminocycloalkyl, carboxycycloalkyl, oxycloalkenyl,thiocycloalkenyl, aminocycloalkenyl, carboxycycloalkenyl, heterocyclic,oxyheterocyclic, thioheterocyclic, aminoheterocyclic,carboxyheterocyclic, oxyaryl, thioaryl, aminoaryl, carboxyaryl,heteroaryl, oxyheteroaryl, thioheteroaryl, aminoheteroaryl,carboxyheteroaryl, oxyalkylaryl, thioalkylaryl, aminoalkylaryl,carboxyalkylaryl, oxyarylalkyl, thioarylalkyl, aminoarylalkyl,carboxyarylalkyl, oxyarylalkenyl, thioarylalkenyl, aminoarylalkenyl,carboxyarylalkenyl, oxyalkenylaryl, thioalkenylaryl, aminoalkenylaryl,carboxyalkenylaryl, oxyarylalkynyl, thioarylalkynyl, aminoarylalkynyl,carboxyarylalkynyl, oxyalkynylaryl, thioalkynylaryl, aminoalkynylaryl orcarboxyalkynylaryl, oxyalkylene, thioalkylene, aminoalkylene,carboxyalkylene, oxyalkenylene, thioalkenylene, aminoalkenylene,carboxyalkenylene, oxyalkynylene, thioalkynylene, aminoalkynylene,carboxyalkynylene, oxycycloalkylene, thiocycloalkylene, amino cycloalkylene, carboxycycloalkylene, oxycycloalkenylene, thiocycloalkenylene,amino cycloalkenylene, carboxycycloalkenylene, oxyarylene, thioarylene,aminoarylene, carboxyarylene, oxyalkylarylene, thioalkylarylene,aminoalkylarylene, carboxyalkylarylene, oxyarylalkylene,thioarylalkylene, aminoarylalkylene, carboxyarylalkylene,oxyarylalkenylene, thioarylalkenylene, amino arylalkenylene,carboxyarylalkenylene, oxyalkenylarylene, thioalkenylarylene,aminoalkenylarylene, carboxyalkenylarylene, oxyarylalkynylene,thioarylalkynylene, aminoarylalkynylene, carboxy arylalkynylene,oxyalkynylarylene, thioalkynylarylene, amino alkynylarylene,carboxyalkynylarylene, heteroarylene, oxyheteroarylene,thioheteroarylene, aminoheteroarylene, carboxyheteroarylene,heteroatom-containing di- or polyvalent cyclic moiety,oxyheteroatom-containing di- or polyvalent cyclic moiety,thioheteroatom-containing di- or polyvalent cyclic moiety,aminoheteroatom-containing di- or polyvalent cyclic moiety,carboxyheteroatom-containing di- or polyvalent cyclic moiety, disulfide,sulfonamide, and the like.

In another embodiment, maleimides, nadimides, and itaconimidescontemplated for use in the practice of the present invention have thestructures IX, X, or XI, where m ranges from 1 to 6, p ranges between 0and 6, and J is selected from:

saturated straight chain alkyl or branched chain alkyl, optionallycontaining optionally substituted aryl moieties as substituents on thealkyl chain or as part of the backbone of the alkyl chain, and where thealkyl chains have up to about 20 carbon atoms;a siloxane having the structure—(C(R³)₂)_(d)—[Si(R⁴)₂—O]_(f)—Si(R⁴)₂—(C(R³)₂)_(e)—,—(C(R³)₂)_(d)C(R³)—C(O)O—(C(R³)₂)_(d)—[Si(R⁴)₂—O]_(f)—Si(R⁴)₂—(C(R³)₂)_(e)—O(O)C—(C(R³)₂)_(e)—,or—(C(R³)₂)_(d)—C(R³)—O(O)C—(C(R³)₂)_(d)—[Si(R⁴)₂—O]_(f)—Si(R⁴)₂—(C(R³)₂)_(e)—C(O)O—(C(R³)₂)_(e)—,where each R³ is independently hydrogen, alkyl or substituted alkyl,each R⁴ is independently hydrogen, lower alkyl or aryl, d ranges from 1to 10, e ranges between 1 and 10, and f ranges from 1 to 50; apolyalkylene oxide having the structure:[(CR₂)_(r)—O—]_(f)—(CR₂)_(s)—  (XII)where each R is independently hydrogen, alkyl or substituted alkyl, r isbetween 1 and 10, s is between 1 and 10, and f ranges from 1 to 50;aromatic groups having the structure:

where each Ar is a monosubstituted, disubstituted, or trisubstitutedaromatic or heteroaromatic ring having in the range of 3 up to 10 carbonatoms, and Z is saturated straight chain alkylene or branched chainalkylene, optionally containing saturated cyclic moieties assubstituents on the alkylene chain or as part of the backbone of thealkylene chain; polyalkylene oxides having the structure:[(CR₂)_(r)—O—]_(q)—(CR₂)₃—  (XIV)where each R is independently hydrogen, alkyl, or substituted alkyl, ris between 1 and 10, s is between 1 and 10, and q falls in the range of1 up to 50; di- or tri-substituted aromatic moieties having thestructure:

where each R is independently hydrogen, alkyl, or substituted alkyl, tfalls in the range of 2 up to 10, u falls in the range of 2 up to 10,and Ar is a monosubstituted, disubstituted, or trisubstituted aromaticor heteroaromatic ring having in the range of 3 up to 10 carbon atoms;aromatic groups having the structures:

where each R is independently hydrogen, alkyl, or substituted alkyl, tis from 2 to 10, k is 1, 2, or 3, g ranges from 1 up to about 50, eachAr is as defined above, E is —O— or —NR⁵— where R⁵ is hydrogen or loweralkyl, and W is straight or branched chain alkyl, alkylene, oxyalkylene,ester, or polyester, a siloxane having the structure—(C(R³)₂)_(d)—[Si(R⁴)₂—O]_(f)—Si(R⁴)₂—(C(R³)₂)_(e)—,—(C(R³)₂)_(d)C(R³)—C(O)O—(C(R³)₂)_(d)—[Si(R⁴)₂—O]_(f)—Si(R⁴)₂—(C(R³)₂)_(e)—O(O)C—(C(R³)₂)_(e)—,or—(C(R³)₂)_(d)—C(R³)—O(O)C—(C(R³)₂)_(d)—[Si(R⁴)₂—O]_(f)—Si(R⁴)₂—(C(R³)₂)_(e)—C(O)O—(C(R³)₂)_(e)—,where each R³ is independently hydrogen, alkyl, or substituted alkyl,each R⁴ is independently hydrogen, lower alkyl, or substituted aryl, dand e are each from 1 to 10, and f is from 1 to 50; a polyalkylene oxidehaving the structure:—[(CR₂)_(r)—O—]_(f)—(CR₂)_(s)—  (XXII)where each R is independently hydrogen, alkyl, or substituted alkyl, rand s each range from 1 to 10, and f is from 1 to 50, optionallycontaining substituents selected from hydroxy, alkoxy, carboxy, nitrile,cycloalkyl, or cycloalkenyl; a urethane group having the structure:R⁷U—C(O)—NR⁶—R⁸—NR⁶—C(O)—(O—R⁸—O—C(O)NR⁶—R⁸—NR⁶—C(O))_(v)—U—R⁸—  (XXIII)where each R⁶ is independently hydrogen or lower alkyl, each R⁷ isindependently an alkyl, aryl, or arylalkyl group having 1 to 18 carbonatoms, each R⁸ is an alkyl or alkyloxy chain having up to about 100atoms in the chain, optionally substituted with Ar, U is —O—, —S—,—N(R)—, or —P(L)_(1,2)-, where R is as defined above, and where each Lis independently ═O, ═S, —OR, or —R, and v ranges from 0 to 50;polycyclic alkenyl; or mixtures of any two or more thereof.

Particularly desirable maleimide compounds for use in the presentinvention include, for example, maleimides having the followingstructures:

Preferred maleimide resins include stearyl maleimide, oleyl maleimideand behenyl maleimide, 1,20-bismaleimido-10,11-dioctyl-eicosane(“X-BMI”), and the like, as well as combinations thereof. Othermaleimides suitable for use herein include those disclosed in U.S. Pat.Nos. 6,034,194 (Dershem) and 6,521,731 (Dershem), the disclosures ofwhich are expressly incorporated herein by reference.

(Meth)acrylates useful as the curable resin may be chosen from a host ofdifferent compounds. As used herein, the terms (meth)acrylic and(meth)acrylate are used synonymously with regard to the monomer andmonomer-containing component. The terms (meth)acrylic and (meth)acrylateinclude acrylic, (meth)acrylic, acrylate, and (meth)acrylate.

The (meth)acrylate component may comprise one or more members selectedfrom a monomer represented by the formula:

where G is hydrogen, halogen, or an alkyl having from 1 to 4 carbonatoms, R¹ has from 1 to 16 carbon atoms and is an alkyl, cycloalkyl,alkenyl, cycloalkenyl, alkaryl, aralkyl, or aryl group, optionallysubstituted or interrupted with silane, silicon, oxygen, halogen,carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, carbamate,amine, amide, sulfur, sulfonate, or sulfone; urethane acrylates orureide acrylates represented by the formula:

where G is hydrogen, halogen, or an alkyl having from 1 to 4 carbonatoms, R⁸ denotes a divalent aliphatic, cycloaliphatic, aromatic, oraraliphatic group, bound through a carbon atom or carbon atoms thereofindicated at the —O— atom and —X— atom or group, X is —O—, —NH—, or—N(alkyl)—, in which the alkyl radical has from 1 to 8 carbon atoms, zis 2 to 6, and R⁹ is a z-valent cycloaliphatic, aromatic, or araliphaticgroup bound through a carbon atom or carbon atoms thereof to the one ormore NH groups; and a di- or tri(meth)acrylate selected frompolyethylene glycol di(meth)acrylates, bisphenol-A di(meth)acrylates,tetrahydrofurane di(meth)acrylates, hexanediol di(meth)acrylate,trimethylol propane tri(meth)acrylate, or combinations thereof.

Suitable polymerizable (meth)acrylate monomers include triethyleneglycol di(meth)acrylate, tripropylene glycol di(meth)acrylate,tetraethylene glycol di(meth)acrylate, diethylene glycoldi(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, pentaerythritol tetra(meth)acrylate, trimethylolpropane tri(meth)acrylate, di-pentaerythritolmonohydroxypenta(meth)acrylate, pentaerythritol tri(meth)acrylate,bisphenol-A-ethoxylate di(meth)acrylate, trimethylolpropane ethoxylatetri(meth)acrylate, trimethylolpropane propoxylate tri(meth)acrylate, andbisphenol-A-diepoxide di(meth)acrylate.

Additionally, mono-functional (meth)acrylate monomers may be used,including tetrahydrofurane(meth)acrylates and di(meth)acrylates,citronellyl(meth)acrylate, hydroxypropyl(meth)acrylate,tetrahydrodicyclopentadienyl(meth)acrylate, triethyleneglycol(meth)acrylate, triethylene glycol(meth)acrylate, and combinationsthereof.

Of course, (meth)acrylated silicones may also be used, provided thesilicone backbone is not so large so as to minimize the effect of(meth)acrylate when cure occurs.

Other (meth)acrylates suitable for use herein include the low viscosityacrylates disclosed in U.S. Pat. No. 6,211,320 (Dershem), the disclosureof which is expressly incorporated herein by reference.

The adhesive composition also includes a curing agent, such as a heatcure catalyst or a radiation cure photoinitiator. The curing agentshould be included in the adhesive composition in an amount between 1 wt% and 30 wt % based on the total weight of the curable resin component.

The heat cure catalyst may be included in the composition to reduce thetemperature at which cure occurs or hasten the degree of cure when theappropriate temperature condition is selected for cure to occur. Theheat cure catalyst may be chosen from free radical catalysts, anioniccuratives, cationic curatives, and combinations thereof. For instance,the free radical catalyst may be chosen from peroxides, azo compounds,and combinations thereof. Particularly desirable peroxide catalystsinclude dicumyl peroxide, dibenzoyl peroxide, 2-butanone peroxide,tert-butyl perbenzoate, di-tert-butyl peroxide,2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, bis(tert-butylperoxyisopropyl)benzene, and tert-butyl hydroperoxide, and azo compoundsinclude 2,2′-azobis(2-methylpropanenitrile),2,2′-azobis(2-methylbutanenitrile), and1,1′-azobis(cyclohexanecarbonitrile).

Commercially available examples of these free radical catalysts includethose promoted by Akzo Nobel, such as the following peroxidesdl-isobutyryl peroxide (CAS No. 3437-84-1), cumyl peroxyneodecanoate(CAS No. 26748-47-0), peroxydicarbonate mixture (CAS No. 105-64-6;19910-65-7; 78350-78-4), 2,4,2-trimethylpentyl-2 peroxyneodecanoate (CASNo. 51240-95-0), cumyl peroxyneoheptanoate (CAS No. 68299-16-1),di-sec-butyl peroxydicarbonate (CAS No. 19910-65-7),tert-butylperoxyneodecanoate (CAS No. 26748-41-4), dibutylperoxydicarbonate (CAS No. 16215-49-9), dicetyl peroxydicarbonate (CASNo. 26332-14-5), di(4-tert-butylcyclohexyl) peroxydicarbonate (CAS No.15520-11-3), di(2-ethylhexyl) peroxydicarbonate (CAS No. 16111-62-9),dimyristyl peroxydicarbonate (CAS No. 53220-22-7), tert-butylperoxyneoheptanoate (CAS No. 26748-38-9), tert-amyl peroxypivalate (CASNo. 29240-17-3), tert-butyl peroxypivalate (CAS No. 927-07-1),di-(3,5,5-trimethylhexanoyl) peroxide (CAS No. 3851-87-4), dilauroylperoxide (CAS No. 105-74-8), dioctanoyl peroxide (CAS No. 762-16-3),didecanoyl peroxide (CAS No. 762-12-9),2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane (CAS No. 13052-09-0),tert-amyl peroxy-2-ethylhexanoate (CAS No. 686-31-7), tert-butylperoxy-2-ethylhexanoate (CAS No. 3006-82-4), dibenzoyl peroxide (CAS No.94-36-0), 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane (CAS No.6731-36-8), 2,2-bis[4,4-di-(tertbutyl-peroxy-cyclohexyl)propane] (CASNo. 1705-60-8), 1,1-di(tert-amylperoxy)cyclohexane (CAS No. 15667-10-4),1,1-di(tert-butylperoxy)cyclohexane (CAS No. 3006-86-8), tert-amylperoxy 2-ethylhexyl carbonate (CAS No. 70833-40-8), tert-butylperoxy-3,5,5-trimethylhexanoate (CAS No. 13122-18-4), tert-butylperoxy-2-methylbenzoate (CAS No. 22313-62-8)2,2-di-(tert-butylperoxy)butane (CAS No. 2167-23-9), tert-butyl peroxyisopropyl carbonate (CAS No. 2372-21-6), tert-butyl peroxy 2-ethylhexylcarbonate (CAS No. 34443-12-4), tert-amyl peroxybenzoate (CAS No.4511-39-1), tert-butyl peroxyacetate (CAS No. 107-71-1), butyl4,4-di-(tert-butylperoxy)valerate (CAS No. 995-33-5), tert-butylperoxybenzoate (CAS No. 614-45-9), di-tert-amyl peroxide (CAS No.10508-09-5), dicumyl peroxide (CAS No. 80-43-3),di-(tert-butylperoxyisopropyl)benzene (CAS No. 25155-25-3),2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (CAS No. 78-63-7),tert-butyl cumyl peroxide (CAS No. 3457-61-2),2,5-dimethyl-2,5-di(tertbutylperoxy)hexyne-3 (CAS No. 1068-27-5),di-tert-butyl peroxide (CAS No. 110-05-4),3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane (CAS No. 24748-23-0),1,1,3,3-tetramethylbutyl hydroperoxide (CAS No. 5809-08-5),diisopropylbenzene monohydroperoxide (CAS No. 26762-93-6), cumylhydroperoxide (CAS No. 80-15-9), tert-butyl hydroperoxide (CAS No.75-91-2), and tert-amyl hydroperoxide (CAS No. 3425-61-4), and thefollowing azo compounds 2,2′-azobis(isobutyronitrile) (CAS No. 78-67-1),2,2′-azobis(2-methylbutyronitrile) (CAS No. 13472-08-7), and1,1′azobis(1-cyclohexanenitrile) (CAS No. 2094-98-6).

The heat cure catalyst may also be an anionic curative, such as thosebroadly described as aza compounds, amine compounds, amide compounds,imidazole compounds, and combinations thereof. More specific examples ofaza compounds include:

More specific examples of amine compounds include aliphatic polyamines,aromatic polyamines, alicyclic polyamines, such as diethylenetriamine,triethylenetetraamine, diethylaminopropylamine, benzyl dimethylamine,m-xylenediamine, diaminodiphenylamine, quinoxaline, isophoronediamine,menthenediamine and combinations thereof.

A more specific example of an amide compound is the functionalizedamide, dicyandiamide.

More specific examples of imidazole compounds include isoimidazole,imidazole, 2-ethyl-4-methylimidazole, 2,4-dimethylimidazole,butylimidazole, 2-heptadecenyl-4-methylimidazole, 2-methylimidazole,2-undecenylimidazole, 1-vinyl-2-methylimidazole, 2-undecylimidazole,2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole,1-propyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole,1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole,1-cyanoethyl-2-phenylimidazole, 1-guanaminoethyl-2-methylimidazole,addition products of an imidazole and methylimidazole, addition productsof an imidazole and trimellitic acid, 2-n-heptadecyl-4-methylimidazole,phenylimidazole, benzylimidazole, 2-methyl-4,5-diphenylimidazole,2,3,5-triphenylimidazole, 2-styrylimidazole, 1-(dodecylbenzyl)-2-methylimidazole,2-(2-hydroxyl-4-t-butylphenyl)-4,5-diphenylimidazole,2-(2-methoxyphenyl)-4,5-diphenylimidazole,2-(3-hydroxyphenyl)-4,5-diphenylimidazole,2-(p-dimethylaminophenyl)-4,5-diphenylimidazole,2-(2-hydroxyphenyl)-4,5-diphenylimidazole,di(4,5-diphenyl-2-imidazole)-benzene-1,4,2-naphthyl-4,5-diphenylimidazole-,1-benzyl-2-methylimidazole, 2-p-methoxystyrylimidazole, and combinationsthereof.

The heat cure catalyst may also be a cationic curative, such as thosebroadly described as organic acids, anhydrides, and Lewis acids. Theorganic acids include phenols, thiophenols, thiols, carboxylic acids,and combinations thereof. The anhydrides include among othershexahydrophthalic anhydride, methyl hexahydrophthalic anhydride,5-(2,5-dioxotetrahydrol)-3-methyl-3-cyclohexene-1,2-dicarboxylicanhydride, and combinations thereof. The Lewis acids include a varietyof materials known in the art as Lewis acids, examples of which arephosphines, alkyl halides, phosphorous esters, boron trifluorideetherate, and the like.

In the event that it is desirable for certain commercial applications tocure the adhesive composition by exposure to radiation in theelectromagnetic spectrum, a photoinitiator should also be included inthe composition. The photoinitiator should be chosen with an eye towardthe range of radiation in the electromagnetic spectrum at which cure isto be triggered. For instance, suitable ranges of radiation in theelectromagnetic spectrum include UV, UV/VIS, VIS, IR, E-beam, X-ray, andmicrowave radiation.

Representative examples of UV and UV/VIS photoinitiators include thoseavailable commercially from Ciba Specialty Chemicals, Tarrytown, N.Y.under the “IRGACURE” and “DAROCUR” tradenames, specifically “IRGACURE”184 (1-hydroxycyclohexyl phenyl ketone), 907(2-methyl-1-[4-(methylthio)phenyl]-2-morpholino propan-1-one), 369(2-benzyl-2-N,N-dimethylamino-1-(4-morpholinophenyl)-1-butanone), 500(the combination of 1-hydroxy cyclohexyl phenyl ketone andbenzophenone), 651 (2,2-dimethoxy-2-phenyl acetophenone), 1700 (thecombination of bis(2,6-dimethoxybenzoyl-2,4,4-trimethyl pentyl)phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one), and 819[bis(2,4,6-trimethyl benzoyl)phenyl phosphine oxide] and “DAROCUR” 1173(2-hydroxy-2-methyl-1-phenyl-1-propane) and 4265 (the combination of2,4,6-trimethylbenzoyldiphenyl-phosphine oxide and2-hydroxy-2-methyl-1-phenyl-propan-1-one); and the visible light [blue]photoinitiators, dl-camphorquinone and “IRGACURE” 784DC. Of course,combinations of these materials may also be employed herein.

Other photoinitiators useful herein include alkyl pyruvates, such asmethyl, ethyl, propyl, and butyl pyruvates, and aryl pyruvates, such asphenyl, benzyl, and appropriately substituted derivatives thereof.

Photoinitiators particularly well-suited for use herein includeultraviolet photoinitiators, such as 2,2-dimethoxy-2-phenyl acetophenone(e.g., “IRGACURE” 651), and 2-hydroxy-2-methyl-1-phenyl-1-propane (e.g.,“DAROCUR” 1173), bis(2,4,6-trimethyl benzoyl)phenyl phosphine oxide(e.g., “IRGACURE” 819), and the ultraviolet/visible photoinitiatorcombination of bis(2,6-dimethoxybenzoyl-2,4,4-trimethylpentyl)phosphineoxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one (e.g., “IRGACURE”1700), as well as the visible photoinitiatorbis([5-2,4-cyclopentadien-1-yl)-bis[2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl]titanium(e.g., “IRGACURE” 784DC).

Additional photoinitiators may be chosen from those available fromSartomer, Inc., Exton, Pa. under the tradenames “ESACURE” and “SARCAT”.Examples include “ESACURE” KB1 (benzil dimethyl ketal), “ESACURE” EB3(mixture of benzoin and butyl ethers), “ESACURE” TZT(trimethylbenzophenone blend), “ESACURE” KIP100F (hydroxy ketone),“ESACURE” KIP150 (polymeric hydroxy ketone), “ESACURE” KT37 (blend of“ESACURE” TZT and KIP150), “ESACURE” KT046 (blend of triphenyl phosphineoxide, “ESACURE” KIP150 and TZT), and “ESACURE” X33 [blend of 2- and4-isopropylthioxanthone, ethyl 4-(dimethyl amino)benzoate and “ESACURE”TZT].

Of course, combinations of such photoinitiators may be used as deemedappropriate by those of ordinary skill in the art.

In addition, the photoinitiator may be a cationic one, which is capableof catalyzing the polymerization of the inventive compositions uponexposure to appropriate radiation conditions. Desirable cationicphotoinitiators for use with the present invention includetriarylsulfonium and diaryliodonium salts containing non-nucleophiliccounterions and aryl diazonium salts, examples of which include4-methoxybenzenediazonium hexafluorophosphate, benzenediazoniumtetrafluoroborate, diphenyl iodonium chloride, diphenyl iodoniumhexafluorophosphate, 4,4-dioctyloxydiphenyl iodoniumhexafluorophosphate, triphenylsulfonium tetrafluoroborate,diphenyltolylsulfonium hexafluorophosphate, phenylditolylsulfoniumhexafluoroarsenate, and diphenyl-thiophenoxyphenylsulfoniumhexafluoroantimonate, and those commercially available from Sartomer,such as “SARCAT” CD 1010 [triaryl sulfonium hexafluoroantimonate (50% inpropylene carbonate)], “SARCAT” DC 1011 [triaryl sulfoniumhexafluorophosphate (50% n-propylene carbonate)], “SARCAT” DC 1012(diaryl iodonium hexafluoroantimonate), and “SARCAT” K185 [triarylsulfonium hexafluorophosphate (50% in propylene carbonate)].

The adhesive composition of the present invention also includes a blockcopolymer additive, which aids in the transfer of the adhesivecomposition from a hydrophobic substrate to a hydrophilic substrate.

Block copolymer additives of the instant invention include those blockcopolymers which comprise both hydrophobic and hydrophilic segments orportions, of the general formula:—[(R¹)_(v)—(R²)_(w)]_(n)—  (XXXII)where each R¹ is independently a hydrophobic olefin, such as ethylene,propylene, 1-butene, 1-hexene, 3-methyl-1-pentene, or 4-methyl-1-penteneor a polymerizable hydrophobic aromatic hydrocarbon such as styrene;each R² is a hydrophilic acid anhydride, such as maleic anhydride; vranges from 1 to 12; w is from 1 to 6; and n is from 1 to 50.

Incorporating into the adhesive composition of the present inventionsuch an additive having the unique structure shown in XXXII causes theadhesive composition to have a greater affinity towards a polar,hydrophilic substrate than towards a hydrophobic substrate, which isgenerally nonpolar. Such effect is derived from the hydrophilic moietywithin the additive molecule that is typically charge-polarized andcapable of entering into a charged interaction with another substrate,substance, or macromolecule in which polar groups dominate. As willbecome more clear by reference to the discussion of the Figures andExamples that follow, this interaction becomes especially importantduring the die pickup stage of the die attach process where it isdesirable for the adhesive layer to be attracted to a semiconductorwafer, the most commonly used of which are hydrophilic, so as to limitthe necessary processing steps.

Preferably, the glass transition temperature (“T_(g)”) of the blockcopolymer additive used in the adhesive composition will be above about40° C. In one embodiment, the T_(g) of the block copolymer additive isbetween about 40° C. and about 155° C.

The T_(g) of a polymer is the temperature at which the polymer becomesbrittle on cooling or soft on heating. More specifically, it defines apseudo second order phase transition in which a polymer yields, oncooling, a glassy structure with properties similar to those of acrystalline material. Above T_(g), the polymer becomes soft and capableof plastic deformation without fracture. While the T_(g) is occasionallydescribed as the “softening temperature” of a polymer, it is notuncommon for the polymer to begin softening at a temperature below theT_(g). This is because, due to the nature of many non-crystallinepolymers, the softening of the polymer may occur over a temperaturerange rather than abruptly at a single temperature value. T_(g)generally refers to the middle point of this range even though thepolymer may begin to soften at a different temperature. For purposes ofthis application, the T_(g) of a polymer refers to the value asdetermined by ASTM E-1356.

In addition to becoming brittle at temperatures below T_(g), a polymeralso generally become drier and less tacky than when that same polymeris heated to a temperature above its T_(g). A tacky polymer will morereadily adhere to a surface upon application of pressure alone than anon-tacky polymer. The importance of incorporating a copolymer additivethat has a T_(g) above 40° C., and thus is dry or only slightly tacky atthis point, will become more apparent by the discussion that follows.

In one embodiment, the block copolymer additive is a styrene maleicanhydride copolymer, represented by the formula:

where v, w, and n are as defined above.

Styrene maleic anhydride copolymers are well known in the art and areavailable from Sartomer Company, Inc. of Exton, Pa. under the trade nameSMA® EF80, for example. Styrene maleic anhydride copolymers representthe copolymerization product of styrene and maleic anhydride and arecharacterized by alternating blocks of styrene and maleic anhydridemoieties. In this particular embodiment of the additive, the styrenemoieties represent the hydrophobic segments and the maleic anhydridemoieties represent the hydrophilic segments.

The ratio of the hydrophobic moieties to the hydrophilic moieties in theblock copolymer additive of the present invention is generally from 2:1(hydrophobic:hydrophilic) to 12:1 (hydrophobic:hydrophilic), such as 6:1to 8:1.

The block copolymer additive may be incorporated into the adhesivecomposition in an amount up to about 50 wt %, desirably from 5 to 40 wt% based on the total weight of the adhesive composition.

The adhesive composition may further include in the range of about 10 upto 90 wt % filler, based on the total weight of the composition. Fillerscontemplated for use in the practice of the present invention mayoptionally be conductive (electrically and/or thermally). Electricallyconductive fillers contemplated for use in the practice of the presentinvention include, for example, silver, nickel, gold, cobalt, copper,aluminum, graphite, silver-coated graphite, nickel-coated graphite,alloys of such metals, and the like, as well as mixtures thereof. Bothpowder and flake forms of filler may be used herein. In flake form, thefiller may have a thickness of less than about 2 microns, with planardimensions of about 20 to about 25 microns. Flake employed herein mayhave a surface area of about 0.15 to 5.0 m²/g and a tap density of about0.4 up to about 5.5 g/cc. In powder form, the filler particles may havea diameter of about 0.5 to 30 microns, such as about 20 microns.

Thermally conductive fillers contemplated for use herein include, forexample, aluminum nitride, boron nitride, silicon carbide, diamond,graphite, beryllium oxide, magnesia, silica, alumina, and the like.

Electrically and/or thermally conductive fillers should be renderedsubstantially free of catalytically active metal ions by treatment withchelating agents, reducing agents, nonionic lubricating agents, ormixtures of such agents. Such treatment is described in U.S. Pat. No.5,447,988 (Dershem), which is expressly incorporated by reference hereinin its entirety.

Optionally, a filler may be used that is neither electrically northermally conductive. Such fillers may be desirable to impart some otherproperty to the formulation such as, for example, reduced thermalexpansion of the cured composition, reduced dielectric constant,improved toughness, viscosity, and the like. Examples of such fillersinclude perfluorinated hydrocarbon polymers (i.e., TEFLON),thermoplastic polymers, thermoplastic elastomers, mica, fused silica,glass powder, spacer elements, polymethyl(meth)acrylate powder,polyamide powder, polymethylsilsesquioxane powder, and the like.

Examples of suitable elastomers that can be added to the adhesivecomposition include acrylic rubbers, butadiene/acrylonitrile rubber,styrene/butadiene rubber, buna rubber, polyisobutylene, polyisoprene,natural rubber, polyurethane, ethylene-vinyl acetate polymers, ethyleneacrylate rubbers, fluorinated rubbers, isoprene-acrylonitrile polymers,chlorosulfonated polyethylenes, and homopolymers of polyvinyl acetate.These elastomers are preferably added before the adhesive compositionundergoes cure.

The adhesive composition may further contain other additives, such asdefoaming agents, leveling agents, dyes, and pigments.

Solvents may also be incorporated into the adhesive composition or usedduring the preparation thereof. Suitable solvents are anhydrous organicsolvents, such as acetone, 2-butanone, ethyl acetate, butyl acetate,tetrahydrofuran, dioxan, benzene, toluene, xylene, ethylbenzene,chlorobenzene, dichlorobenzene, dimethylformamide, dimethyl acetamide,or N-methylpyrrolidone. In particular, acetone, 2-butanone,tetrahydrofuran, ethyl acetate, or chlorobenzene are useful.

Referring to the drawings in which like reference characters refer tolike parts throughout the several views thereof, an assembly 30 isdepicted in FIGS. 1 and 2. Depicted in FIGS. 3 and 4 are methods offorming an assembly 30.

Generally speaking, assembly 30 includes a semiconductor chip die 20 anda layer of adhesive composition 2, which may be partially cured.

Chip die 20 is produced by dicing, or segmenting by sawing, a wafer intosmaller segments or pieces. These individual segments of the wafer arewhat are known as the chip dies 20. Chip die 20 may be constructed ofany material known in the art. For example, chip die 20 may beconstructed of silicon, germanium, or the like, but the most common issilicon. Chip die 20 may also be coated with a passivation materialwhich is capable of inhibiting environmental corrosion. The coating ofchip die 20 may be accomplished before or after the dicing of the waferinto the individual dies 20.

Chip die 20 includes opposing first and second surfaces, including chipsurface 22 as a first surface and attach surface 24 as a second surface.On attach surface 24 is disposed adhesive layer 2.

Adhesive layer 2 can be applied directly to attach surface 24. Thisdirect application can be accomplished by any method known in the art,including ink jet printing, stencil printing, screen printing, or spraycoating. The method of application should uniformly coat the attachsurface 24. Such direct application of adhesive layer 2 to attachsurface 24 can be accomplished before or after the dicing process.Adhesives which are applied directly to the chip die are known in theart as “pre-applied” adhesives.

Once the adhesive layer 2 is applied directly to attach surface 24, theadhesive layer 2 can be partially cured or B-staged. Conditions suitablefor curing the adhesive layer 2 include subjecting the adhesive layer 2to a temperature of at least about 100° C., but less than about 300° C.,for about 15 up to about 70 minutes.

Alternatively, adhesive layer 2 can first be applied to an intermediatesubstrate 50, such as a wafer dicing tape or film or a wafer supportingtape or film. An example of such a substrate 50 with the adhesive layer2 applied thereto is shown in FIG. 2.

In one embodiment, the intermediate substrate 50 is a polyolefin film,examples of which include polyethylene, polyvinyl chloride, polybutene,polybutadiene, polyurethane, polyester, polyamide, and copolymersthereof. The polyolefin film may optionally be a laminate of severalfilms. While there are no particular limitations concerning thethickness of the polyolefin film, it is usually about 10 to 300 μm, suchas about 50 to 200 μm.

The adhesive layer 2 is applied to the surface of the polyolefin filmusing any applicable method, including rolling, spray printing, or thelike. If the adhesive composition forming the adhesive layer 2 containsa high amount of solvent, the adhesive layer 2 and the polyolefin filmare subjected to a B-staging process, which removes the excess solventfrom the adhesive composition without significantly advancing cure ofthe resins. A typical B-staging time may be from about 1 to about 10minutes at a temperature of between about 70 and 90° C. The length ofthe B-staging may vary depending on the amount of solvent present in theadhesive composition and also on the temperature selected. Once thisprocess is complete, the adhesive layer 2 will be film-like in texture.The adhesive layer 2 can then be laminated to the surface of theintermediate substrate 50 under conventional laminating conditions.Similar products, which combine a polyolefin tape with an adhesive layerdisposed thereon, are known in the industry as 2-in-1 tape, examples ofwhich include Hysol® QMI 5100/5200 available commercially from Henkel.

Referring now to FIG. 3, a method of forming the assembly 30 will bedescribed. Adhesive layer 2 is applied to intermediate substrate 50 toform a 2-in-1 tape product as described above. Next, a pre-diced wafer10 is placed onto adhesive layer 2 and a backside lamination processaffixes the pre-diced wafer 10 to the substrate 50 with the adhesivelayer 2 creating an interface between the backside of the wafer and theintermediate substrate 50. Conditions suitable for the backsidelamination process include subjecting the adhesive layer 2 to atemperature of between about 32 and about 100° C., such as between 50and 60° C., and applying mild pressure to the top of the wafer. Duringlamination, the adhesive layer 2 softens and wets the surface of thepre-diced wafer 10 generating enough adhesiveness between the pre-dicedwafer 10 and the intermediate substrate 50 to hold the pre-diced wafer10 in place relative to the intermediate substrate 50 during subsequentprocessing of the wafer. The adhesive composition does not undergocomplete cure during the backside lamination process but partial curemay occur.

Next, the pre-diced wafer 10 undergoes a dicing process. During waferdicing, the dicing saw 60 or, optionally, saws (not shown), cutscompletely through the wafer 10 and the adhesive layer 2. As mentionedabove, the adhesive layer 2 provides sufficient adhesion strength tohold the pre-diced wafer 10 in place relative to the intermediatesubstrate 50 during the dicing process. The dicing process segments thewafer into a plurality of individual chip dies 20 and to the backside ofeach chip die 20 is a correspondingly segmented portion of the adhesivelayer 2.

After dicing is complete, the chip dies 20, are removed from theintermediate substrate 50 by a process known as die pickup or diepick-and-place. Die pickup is generally accomplished through the use ofpick and place equipment and usually involves first loosening theindividual dies 20 from the intermediate substrate 50 and then liftingthe dies 20 with a pickup tool 80 using, for example, suction. Diepickup may be carried out at any temperature, but a temperature near orabove room temperature is most common.

A die 20 can be loosened from the intermediate substrate 50 in variousways. For one, as shown in FIG. 3, the die 20 can be loosened from theintermediate substrate 50 by applying pressure from underneath the die20 through the use of an ejector tool 70. The ejector tool 70 may becomprised of, for example, a single pin-like element or may be comprisedof a set of pin-like elements. Alternatively, the die 20 can be loosenedfrom the intermediate substrate 50 by applying radiation to the adhesivelayer 2 sufficient to cure the adhesive. Once cured, the adhesive forceof the adhesive becomes weaker, making it easier to remove the die 20using a die pickup tool 80. For example, if the adhesive compositionincludes a photoinitiator making it susceptible to cure upon exposure toradiation in the UV range, application of UV radiation to the adhesivelayer 2 will cause the adhesive to cure, thus weakening its adhesivenessto the dicing tape.

Desirably, the segment of adhesive layer 2 on the backside of each ofthe chip dies 20 will transfer from the intermediate substrate 50 to thedie 20 during die pickup and thus remain on the backside of the die 20after pickup is complete. Such an effect will make the subsequentplacement of the die 20 much simpler since the transferred adhesivelayer 2 can act as the adhesive necessary to bond the die at anotherlocation, foregoing the need of the additional step of dispensing a newamount of adhesive to bond the die 20 at its new location.

If during die pickup the adhesive layer 2 is tacky, it is much moreunlikely that it will cleanly transfer to the backside of the die 20.Instead, a tacky adhesive layer, or at least a portion thereof, willremain adhered or stuck to the surface of the intermediate substrate 50during die pickup. As explained previously, the adhesive compositionwill be drier and less tacky if it is in a solid, crystalline-likestate. Because the die pickup process is usually conducted at roomtemperature (taken as 32° C.), it is preferential that the adhesivecomposition achieve a solid-like state at this temperature. The adhesivecomposition described herein achieves such a property because theadhesive is in a relatively crystalline state at temperatures belowabout 40° C. Thus, if die pickup is performed at room temperature, theadhesive layer 2 will be substantially non-tacky.

After removing the die 20 from the intermediate substrate 50, the die 20can be placed on another substrate, such as a circuit board 90, duringdie placement or stacked onto another die 20 to create a stacked dieassembly (such as described in U.S. Pat. Nos. 5,140,404, 5,286,679,5,323,060, and 6,465,893, the disclosures of each of which being herebyexpressly incorporated herein by reference). Optionally, the surfaceonto which the die 20 will be placed is heated prior to receiving thedie 20 so that when the adhesive layer 2, which is attached to thebackside of the die 2, contacts the heated surface, the adhesive softensand wets the placement surface. Sometime after placement of the die 20,the adhesive layer 2 is cured by, for example, subjecting it to atemperature of between about 130 and 180° C. for a period of betweenabout 30 and 90 minutes.

FIG. 4 represents another method of preparing the assembly 30. In FIG.4, an ink jet printer is used to apply an adhesive layer 2 directly ontoa pre-diced wafer 10. This process is known in the industry as inkjetting or ink jet printing. During ink jet printing, the adhesivecomposition is loaded into a cartridge in a ink jet printer, such as athose manufactured by FUJIFILM Dimatix®, Inc., a pre-diced wafer 10 isfed through the printer, and the printer dispenses the adhesive onto thesurface of the pre-diced wafer 10. The adhesives used for ink jettinghave a much lower viscosity than those adhesives used for otherapplication methods, such as the ones discussed above involving stencilprinting or 2-in-1 tapes. For example, the viscosity of an adhesivesuitable for use in ink jetting is typically between 1 and 20 cps, suchas 2 to 10 cps. In order to achieve such low viscosities, it is usuallynecessary to include a high percentage of solvent material in adhesivesused for ink jetting.

After the ink jet printer has applied an adhesive layer 2 onto apre-diced wafer 10, the wafer 10 undergoes a drying process in order torid the adhesive composition of much of the solvent. Removal of thesolvent increases the viscosity of the adhesive layer 2 and theresultant adhesive layer 2 becomes more film-like in consistency. Atypical drying time may be about 1-10 minutes at a temperature of about80° C. The length of drying time may vary depending on the amount ofsolvent present in the adhesive composition and also on the temperatureselected for the drying process.

Subsequent to the drying process, the pre-diced wafer 10 with adhesivelayer 2 applied thereto is placed onto an intermediate substrate 50,such as those described above, and undergoes backside lamination toadhere the pre-diced wafer 10 relative to the intermediate substrate 50.Conditions suitable for the backside lamination process includesubjecting the adhesive layer 2 to a temperature of between 32° C. and100° C., such as between 50° C. and 60° C., and applying mild pressureto the top of the wafer. During lamination, the adhesive layer 2 softensand wets the surface of the intermediate substrate 50 generating enoughadhesiveness between the pre-diced wafer 10 and the intermediatesubstrate 50 to hold the pre-diced wafer 10 in place relative to theintermediate substrate 50 during subsequent processing of the wafer. Theadhesive composition does not undergo complete cure during the backsidelamination process but partial cure may occur.

Dicing, die pickup, and die placement can then proceed in a mannersimilar to that described above with respect to the method of FIG. 3.

The present invention will be more readily appreciated with reference tothe examples which follow.

EXAMPLES

Adhesive compositions were prepared according to the formulationsrecited below in Tables 1 and 2. The silane modified epoxy was made inaccordance with the synthetic scheme set forth in FIG. 5.

TABLE 1 Sample Component A B C D E F G H I J K L M N O P silane modifiedepoxy 48.5 34 24.2 21.8 19.4 16 13.4 11.9 7.5 5.7 18.5 17.4 16.4 18.514.2 18.5 thermoplastic polyurethane¹ 13.2 9.2 6.6 5.9 5.3 4.4 3.6 3.32.1 1.6 5.0 4.7 4.4 5.0 3.8 5.0 Bisphenol F epoxy 26.3 18.4 13.2 11.810.5 8.7 7.3 6.5 4 3.1 10.0 9.4 8.9 10.0 7.7 10.0 Diaminodiphenylsulfone 12 8.4 6 5.5 4.8 8.9 3.4 2.9 1.8 3.2 4.7 4.4 4.1 4.7 3.6 4.7styrene maleic copolymer² 0 0 15 20 25 20 12.3 15.4 9.6 7.1 17 16 15 1713 17 2-Butanone 0 30 35 35 35 30 60 60 75 75 29.8 28.0 26.3 29.8 22.829.8 DCPD Epoxy³ 0 0 0 0 0 12 0 0 0 4.3 0 0 0 0 0 0polymethysilsesquioxane 0 0 0 0 0 0 0 0 0 0 15 20 25 0 0 0 powder⁴ PMMApowder⁵ 0 0 0 0 0 0 0 0 0 0 0 0 0 15 0 0 Silica 0 0 0 0 0 0 0 0 0 0 0 00 0 35 0 Polyamide powder⁶ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 ¹EstagripST80A from Noveon, Cleveland, OH ²SMA EF80 from Sartomer ³Tactix 556from Huntsman Chemical ⁴Tospearl 120 from GE Silicones ⁵Tex Matte fromShamrock Technology, Newark, NJ ⁶Orgasol powder from Arkema,Philadelphia, PA

TABLE 2 Sample Component Q R S Acrylic Polymer¹ 11.47 5.7 styrene maleiccopolymer² 0 5.7 20.6 Solid acrylic monomer³ 2.3 2.3 Liquid epoxyacrylate⁴ 9.2 9.2 Peroxide⁵ 0.23 0.23 Defoamer⁶ 0.13 0.13Silane-modified epoxy 0.1 0.1 SO-E2 Silica 2.25 2.25 2-Butanone 74.474.4 36.2 Bismaleimide⁷ 10 Silane-modified epoxy 2.3 DCPD Epoxy⁸ 19.1Diaminodiphenyl sulfone 4.9 Ethylene acrylate rubber⁹ 5.9 Organicperoxide 1 ¹M6003 BMA polymer from Negami Chemical ²SMA EF80 fromSartomer ³SR633 from Sartomer ⁴Ebecryl3600 from Cytec ⁵Dicumyl peroxidefrom Aldrich ⁶PC 1344 defoamer from Monsanto ⁷X-BMI Resin from Henkel⁸Tactix 556 from Huntsman Chemical ⁹VAMAC G from DuPont

Samples A and B were prepared by adding silane-modified epoxy andthermoplastic urethane in a glass mixer heated by an oil bath at atemperature of 120° C. and mixing until both the epoxy and the urethanewere in complete solution. Next, diaminodiphenyl sulfone was added andthe mixture was mixed until the diaminodiphenyl sulfone was completelydissolved. The mixture was then cooled to 25° C., and the butanone wasadded, and the mixture was mixed for an additional 30 minutes.

Samples C-P, which each contains an amount of styrene maleic anhydrideas a block copolymer additive, were prepared by dissolving the styrenemaleic anhydride in 2-butanone at a temperature of 25° C. and separatelycombining the other components using the same procedure as discussedabove with respect to Samples A and B. The styrene maleic anhydridesolution was then added to the epoxy solution and the resulting mixturewas mixed at a temperature of 25° C. for a period of time of 30 minutes.

Sample Q was prepared by adding the acrylic monomer, acrylic polymer,epoxy acrylate, and silane-modified epoxy in a glass mixer heated by anoil bath at a temperature of 120° C. and mixing until the componentswere in complete solution. Next, the peroxide was added and the mixturewas mixed until the peroxide was completely dissolved. The mixture wasthen cooled to a temperature of 25° C., the rest of the components wereadded, and the mixture was mixed for an additional 30 minutes.

Sample R was prepared in a manner similar to Sample Q but the styrenemaleic anhydride was first dissolved in 2-butanone at a temperature of25° C. and then added to the solution which contained the othercomponents and mixed at 25° C. for 30 minutes.

Sample S was prepared by dissolving the styrene maleic anhydride in2-butanone at a temperature of 25° C. to form a styrene maleic anhydridesolution. Separately, the bismaleimide, silane-modified epoxy, and DCPDepoxy were placed in a glass mixer heated by an oil bath at 120° C. andmixed until all were in complete solution. Next, the diaminodiphenylsulfone and peroxide were added and the mixture was mixed until thediaminodiphenyl sulphone and peroxide were completely dissolved. Themixture was then cooled to a temperature of 25° C., the rest of thecomponents were added, and the mixture was mixed for an additional 30minutes. The styrene maleic anhydride solution was then added and theresulting mixture was mixed at a temperature of 25° C. for 30 minutes.

The sample adhesive compositions were evaluated for various propertiesand the results of these evaluations are displayed in Table 3.

TABLE 3 Property Film Si Wafer- B-Stage Film Film Melting thickness FilmAdhesive Viscosity Conditions Characteristic Point After B after releaseLaminating Sample Type¹ (cps) (° C./min.) after B-Stage Stage (° C.)(μm) Temp (° C.) A PAA 15000 150/60 Tacky 80 50-100 50-60 B DDF 200150/60 Tacky 80 50-100 50-60 C DDF 240 80/5 Less tacky 80 50-100 50-60 DDDF 280 80/5 Slightly tacky 80 50-100 50-60 E DDF 460 80/5 Dry 80 50-10050-60 F DDF 340 80/5 Slightly tacky 80 50-100 50-60 G Ink Jet 8 80/5Slightly tacky 80 5 50-60 H Ink Jet 9 80/5 Dry 80 5 50-60 I Ink Jet 380/5 Slightly tacky 80 5 50-60 J Ink Jet 5 80/5 Slightly tacky 80 550-60 K DDF 450 L DDF 620 M DDF 780 N DDF 400 O DDF 690 P DDF 900 QTacky R Not tacky S DDF 800 80/5 Slightly tacky 80 50-100 50-60 QMI5100² DDF Dry 130 75 60 Property % Adhesive % Voids in Modulus AdhesiveTransferred to Die Attach Die Attach @ room T_(g) (° C.) Strength @ Sidie during Temp. bond after temp. After 245° C. Sample pickup (° C.)placement (Gpa) Cure (N/m²) A  0% NA 2.3 84 2.4 × E6 B  0% NA 2.3 84 2.4× E6 C  0% NA 2 77 2.0 × E6 D 100% 80 0% 2.2 80 2.0 × E6 E 100% 80 0%2.4 85 2.2 × E6 F 100% 80 0% 3.5 130 2.5 × E6 G 100% 80 0% 2.2 80 2.0 ×E6 H 100% 80 0% 2.4 85 2.2 × E6 I 100% 80 0% 2.4 80 2.2 × E6 J 100% 800% 3.5 130 2.5 × E6 K 100% 0% L 100% less than 5% M 100% less than 5% N100% less than 5% O 100% 20%  P 100% 15%  Q  0% NA R OK OK S 100% 80 0%1.2 30 1.0 × E6 QMI 5100² 100% 120 30%  ¹PAA = pre applied adhesive; DDF= dicing die attach film; Ink Jet = ink jet printing applied adhesive²Hysol ® 5100/5200 dicing die attach film available commercially fromHenkel

During each of the tests in Table 3, the pre-diced wafer used was asilicon 3 mil. polished wafer having a size of 250×300 mil. This waferrepresents a hydrophilic substrate.

Sample A, which had a high viscosity due to the absence of solvent, wasapplied directly to a pre-diced wafer using stencil printing and wasthen B-staged at 150° C. for 60 minutes. Because no solvent was present,the volume of the adhesive layer remained constant throughout B-staging.After B-staging was complete, the adhesive layer had a dome-like shapeand a tacky texture. The pre-diced wafer, with the adhesive layerapplied thereto, was then placed onto a polyolefin dicing tape with theadhesive layer forming an interface between the wafer and the tape.Backside lamination by a Ultron® UH114-8 wafer laminator operating at awafer laminating temperature of 65° C. (actual temperature on wafer top)and mild pressure applied by manual rolling secured the wafer to thedicing tape. The wafer and the adhesive layer were then diced with aDISCO® DAD 3350 dicing machine operating with the following parameters:

35,000 rpm 20 mm/sec. 1st cut: Blade 27H EFF, Cut Depth 50 μm into SiDie 2nd cut: Blade 27H EBB, Cut Depth 30 μm into Dicing Tape Water Jet:1.3 L/min.

After dicing was complete, the individual chip dies were picked up usinga Datacon® 2200 apm+ Multi-Chip Die Bonder operating with the followingparameters:

Needle: Four Round Ejector Pins Pickup Tool: Flat Ejection Speed: 15mm/sec. Needle End Point: 1.0 mm Pickup Time: 0.1 sec.

After the pickup process, the amount of the adhesive that remained onthe backside of the individual chip dies was visually evaluated. It wasobserved that 0% of the adhesive layer remained affixed to the chip dieafter die pickup. Because the chip die could not undergo subsequent dieplacement without first dispensing an additional amount of adhesiveeither on the die or on the placement surface, the die attach propertiesof Sample A were not evaluated.

Samples B-F were each applied as a thin layer directly onto a polyolefindicing tape in order to create a 2-in-1 dicing die attach film (DDF).B-staging at 80° C. for 5 minutes removed most of the solvent from theadhesive leaving a film-like layer of adhesive ranging from tacky forthe sample that did not contain any styrene maleic anhydride blockcopolymer additive (Sample B) to dry for the sample that contained 25 wt% styrene maleic anhydride block copolymer additive (Sample E) intexture. The adhesive layer was laminated to the dicing tape at atemperature of 55° C. and mild pressure using a GBC® HeatSeal™ HP600laminator.

A pre-diced silicon wafer was then placed onto the adhesive layer andbackside lamination using the Ultron® UH114-8 wafer laminator describedabove secured the wafer relative to the tape surface. The wafer wasdiced with a DISCO® DAD 3350 under the same dicing parameters as above.

After dicing, the individual chip dies were picked up using a Datacon®2200 apm+Multi-Chip Die Bonder operating under the same parameters asabove. After pickup, the amount of adhesive that transferred from thedicing tape to the chip die was evaluated by visually examining the dieand its footprint left on the dicing tape to determine if any residualadhesive remained on the dicing tape and was thus not transferred to thedie. The adhesive of Sample B, which did not contain any styrene maleicanhydride copolymer additive, exhibited 0% transfer to the chip dieduring pickup. The same result was observed for the adhesive of SampleC, which contained 15 wt % styrene maleic anhydride copolymer. However,the adhesives of Samples D-F, which contained 20 wt %, 25 wt %, and 20wt % styrene maleic anhydride copolymer, respectively, each exhibited100% transfer of the adhesive layer from the dicing tape to theindividual chip dies during die pickup.

The individual chip dies of Samples D-F underwent die placement onto asubstrate using the Datacon® 2200 apm+ Multi-Chip Die Bonder. Dieplacement was conducted at 80° C. and 0.5 kg pressure for 1 second.After die placement was complete, the adhesive composition was cured at165° C. for 60 minutes to secure the chip die to the substrate. Aftercompletion of the die placement process, acoustic microscopy imageanalysis was conducted to determine the coverage area of the adhesive atthe bond interface between the chip die and the substrate. Full adhesivecoverage, meaning few to no voids exist in the bond interface layeracross the bottom surface area of the chip die, is preferential becauseit generally creates a stronger bond between the chip die and thesubstrate and also better thermal and/or electrical conductivity acrossthe interface. Samples D, E, and F each exhibited full adhesivecoverage.

Samples G-J were prepared for application in an ink jet printingoperation. The viscosity of each of these sample adhesives was muchlower than in the pre-applied adhesive and dicing die attach filmapplications of Samples A-F. This low viscosity was the result of a highamount of solvent added to the adhesive composition. After preparation,these adhesives were loaded into a Dimatix® materials printer and inkjetted directly onto the surface of a pre-diced silicon wafer. Becausethe ink jet type adhesives have a high amount of solvent, the adhesivelayer was dried at 80° C. for 5 minutes after application onto the wafersurface in order to form a thin, film-like adhesive layer. The resultinglayer ranged from slightly tacky to dry, as noted in Table 3. Thepre-diced wafer was then applied to a polyolefin dicing tape, laminated,and diced according to the procedures discussed above, except that nowthe adhesive layer is on the pre-diced wafer rather than the tapesurface. Subsequent to the dicing process, the chip dies underwent diepickup and placement onto a substrate in a manner similar to thatdescribed above.

With each of Samples G-J, the adhesive layer remained on the surface ofthe die after die pickup and no residual adhesive remained on thesurface of the dicing tape. In addition, each of Samples G-J exhibitedcomplete bond coverage after die placement with no observable voids inthe bond interface.

Because of the high solvent percentage in Samples G-J, complete releaseof the adhesive layer was observed even when the amount of styrenemaleic anhydride copolymer in the adhesive was relatively low. Forexample, Sample C contained 15 wt % styrene maleic anhydride copolymerbut complete release of the adhesive layer was not observed while SampleJ, which contained only 7.1 wt % styrene maleic anhydride copolymer,demonstrating complete release of the adhesive layer to the chip die,suggesting that the amount of additive required to act as a releaseagent may be dependent upon the viscosity of the composition.

Samples K-P show the effect of adding various filler materials to theadhesive compositions of the present invention used in the dicing dieattach application. The filler materials affected the viscosity of theadhesive compositions. In each of these Samples, the adhesive layer wascompletely transferred to the chip die surface during die pickup. Afterplacement of the die, the percentage of voids in the bond interfaceranged from 0% in Sample K to 20% in Sample O.

In Samples Q and R, the curable resin component included acrylicmonomer. Sample Q did not include any styrene maleic anhydride blockcopolymer additive while Sample R included 25 wt % styrene maleicanhydride. The adhesive composition of Sample Q was tacky in texturewhile the adhesive film of Sample R, which contained styrene maleicanhydride as the block copolymer additive, was not tacky. After diepickup was completed, it was observed that the adhesive of Sample Q didnot release from the dicing film. The adhesive of Sample R, however,exhibited satisfactory release from the dicing film during die pickup.In addition, after die placement, it was observed that the adhesive ofSample R provided adequate coverage across the die attach bond with fewto no voids present.

In Sample S, the curable resin component of the adhesive includedbismaleimide, and more specifically X-BMI, a proprietary bismaleimidecompound available from Henkel. This adhesive was tested for use in adicing die attach film application in a manner similar to Samples C-F.The adhesive composition of Sample S was only slightly tacky in texture.After die pickup, it was observed that the adhesive of Sample Sexperienced complete release from the dicing tape to the die surface. Inaddition, no voids were observed along the bond interface after dieplacement.

QMI 5100 is a commercially available dicing die attach film product fromHenkel. QMI 5100 is comprised of a pressure sensitive adhesive layer onexpandable polyolefin dicing tape. As shown in Table 3, completeadhesive transfer from the dicing tape to the chip die during die pickupwas achieved using QMI 5100. However, after the die placement process iscomplete, up to 30% voids were observed in the bond interface. QMI 5100and other currently available dicing die attach film products include ahigh molecular weight resin which is necessary to achieve adequaterelease during die pickup. However, these high molecular weight resinsdo not flow as freely during die placement, which may result in anincomplete die attach bond interface. The adhesives of the instantinvention, meanwhile, allow complete adhesive film transfer to becoupled with a low-void bond interface after die placement since theblock copolymer additive aids in the release of the adhesive film, evenif it comprised of lower molecular weight resins.

What is claimed is:
 1. A composition comprising: a first epoxycomponent; a second silane-modified epoxy component, where the secondcomponent arises from reaction of an aromatic epoxy resin and an epoxysilane in a weight ratio of from about 1:10 to about 10:1, wherein theepoxy silane is embraced by the following structure:R¹—Si(OR²)₃ wherein R¹ is an oxirane-containing moiety and R² is analkyl or alkoxy-substituted alkyl, aryl or aralkyl group having from 1to ten carbon atoms; a thermoplastic urethane; and diaminophenylsulfone.
 2. The composition of claim 1, in the form of a pre-appliedadhesive.
 3. The composition of claim 1, wherein the first epoxycomponent is a solid epoxy resin derived from the group consisting ofbisphenol A, bisphenol F, bisphenol S, tetramethylbiphenyl, biphenyl,and novolacs; or wherein the epoxy component is tris(2,3-epoxy-propyl)isocyanurate or a dicyclopentadiene (“DCPD”) epoxy resin, orcombinations thereof.